But an industry audience brought together in a civic centre to watch the opening via a videolink with the 209MW windfarm, watched in silence as the turbines failed to turn.

Half a minute later as a breeze developed and the first blade slowly began to rotate, there were cheers of relief as much as joy from executives of the developer, Dong, and its guests.

Horns Rev 2, 30 kilometres (16.2 nautical miles) off the coast of Jutland, Denmark, is the largest offshore windfarm but its position will be eclipsed when the Greater Gabbard field comes on stream in Britain followed later by the much larger London Array.

The 3.5bn kroner (£420m) development has some extra significance because it has been put together by a Danish oil company.

Fritz Schur, chairman of Dong, said his firm would triple its production capacity of clean energy by 2020. "Establishing Horns Rev 2 is an important milestone in Dong Energy's gradual transition from conventional to green power generation," he said.

Critics of wind power complain that it is unreliable because of the intermittent nature of wind. But wind executives say this will only be a problem if it replaces most other energy sources. Even then they believe that other forms of clean energy can be used to take up the slack via a much-vaunted super grid to link the whole of Europe's electricity supply.

Niels Bergh-Hansen, head of wind power at Dong, shrugged off the slow start at Horns Rev 2. "The turbines are very heavy and it always takes time to get started. I had faith in the team out there and never doubted it would work fine."

You need to be signed in to post a comment.

If you have an account you can login here, if you haven't registered yet you can register here.